[PATCH 09/14] KVM: arm64/sve: Simplify KVM_REG_ARM64_SVE_VLS array sizing

From: Dave Martin <Dave.Martin@arm.com>
To: kvmarm@lists.cs.columbia.edu
Cc: Okamoto Takayuki <tokamoto@jp.fujitsu.com>,
	Christoffer Dall <cdall@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Zhang Lei <zhang.lei@jp.fujitsu.com>,
	Julien Grall <julien.grall@arm.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 09/14] KVM: arm64/sve: Simplify KVM_REG_ARM64_SVE_VLS array sizing
Date: Fri, 12 Apr 2019 17:28:13 +0100	[thread overview]
Message-ID: <1555086498-26691-10-git-send-email-Dave.Martin@arm.com> (raw)
In-Reply-To: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com>

A complicated DIV_ROUND_UP() expression is currently written out
explicitly in multiple places in order to specify the size of the
bitmap exchanged with userspace to represent the value of the
KVM_REG_ARM64_SVE_VLS pseudo-register.

To make this more readable, this patch replaces these with a single
define.

Since the number of words in a bitmap is just the index of the last
word used + 1, this patch expresses the bound that way instead.
This should make it clearer what is being expressed.

Since use of DIV_ROUND_UP() was the only reason for including
<linux/kernel.h> in guest.c, this patch removes that #include.

No functional change.

Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
 arch/arm64/kvm/guest.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 73044e3..f025a2f 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -23,7 +23,6 @@
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/nospec.h>
-#include <linux/kernel.h>
 #include <linux/kvm_host.h>
 #include <linux/module.h>
 #include <linux/stddef.h>
@@ -209,8 +208,10 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 #define vq_word(vq) (((vq) - SVE_VQ_MIN) / 64)
 #define vq_mask(vq) ((u64)1 << ((vq) - SVE_VQ_MIN) % 64)
 
+#define SVE_VLS_WORDS (vq_word(SVE_VQ_MAX) + 1)
+
 static bool vq_present(
-	const u64 (*const vqs)[DIV_ROUND_UP(SVE_VQ_MAX - SVE_VQ_MIN + 1, 64)],
+	const u64 (*const vqs)[SVE_VLS_WORDS],
 	unsigned int vq)
 {
 	return (*vqs)[vq_word(vq)] & vq_mask(vq);
@@ -219,7 +220,7 @@ static bool vq_present(
 static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
 	unsigned int max_vq, vq;
-	u64 vqs[DIV_ROUND_UP(SVE_VQ_MAX - SVE_VQ_MIN + 1, 64)];
+	u64 vqs[SVE_VLS_WORDS];
 
 	if (!vcpu_has_sve(vcpu))
 		return -ENOENT;
@@ -243,7 +244,7 @@ static int get_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
 	unsigned int max_vq, vq;
-	u64 vqs[DIV_ROUND_UP(SVE_VQ_MAX - SVE_VQ_MIN + 1, 64)];
+	u64 vqs[SVE_VLS_WORDS];
 
 	if (!vcpu_has_sve(vcpu))
 		return -ENOENT;
-- 
2.1.4
